The invention described herein may be manufactured and used by or for the Government of the United States of America for Governmental purposes without the payment of any royalties thereon or therefor.
(1) Field of the Invention
The invention relates to elastomeric ejection systems for submarines, and is directed more particularly to such a system including an improved check valve affording substantially quieter operation than traditional check valves.
(2) Description of the Prior Art
Elastomeric ejection systems for submarines are generally known and are used to launch torpedoes and other weapons and vehicles, hereinafter referred to collectively as xe2x80x9cbodiesxe2x80x9d, from the torpedo tubes. Examples of such systems are illustrated and described in U.S. Pat. No. 4,848,210, issued Jul. 18, 1989 in the name of Laurent C. Bissonnette, in U.S. Pat. No. 5,200,572, issued Apr. 6, 1993, in the names of Laurent C. Bissonnette et al, and in U.S. Pat. No. 5,438,948, issued Aug. 8, 1995, in the name of Paul E. Moody, all incorporated herein by reference.
In such systems the driving force for launching the bodies from the torpedo tubes is pressurized seawater, and the pressurization of the seawater is accomplished by storing a charge of seawater in an expandable elastomeric disk or structure. To charge the elastomeric disk or structure with seawater, a sea valve is provided in communication with a charging pump which is in communication with an inlet cylinder which, in turn, is in communication with the elastomeric disk or structure.
Between the charging pump and the inlet cylinder there is a check valve which, in a charging operation, allows seawater to flow from the pump to the inlet cylinder. However, once the elastomeric disk or structure is filled to capacity and the pressure in the elastomeric disk or structure and the inlet cylinder reaches launch pressure, the pump shuts down and a check valve shuts to prevent back-flow through the charging pump. The check valve typically makes a discernible noise upon closure. The noise can be detected by sensitive listening devices, permitting a target vessel a brief period of time in which to take evasive maneuvers in hopes of reducing the chances of a successful attack.
In U.S. Pat. No. 6,443,182, issued Sep. 3, 2002, in the name of Lance Hathcock, a non-slamming check valve is disclosed. While the disclosed valve has a dampening effect on the wear produced by the valve closure, the noise of the valve is shifted from the closure to the dampening operation.
Specifically, a bleed hole (item 36 of the cited reference) in a dampening chamber (item 28) provides the pressure release of the dampening operation. The problem is that the passage area of the bleed hole is minimal in comparison to the remaining pressurized area of the valve (item 12). In a high-pressure environment, such as an elastomeric ejection system, a pressure release through the bleed hole may be loud, therefore not successfully accomplishing noise reduction. Furthermore, the comparatively minimal size of the bleed hole may inhibit the rapid closure response required by an elastomeric ejection system allowing the elastomer to deflate from its full volume effectively decreasing the energy available for launch.
Accordingly, there is a need for an elastomeric ejection system in which the check valve operates at a much lower sound level and in a rapid operation when the elastomeric disk or structure is made ready for launch.
An object of the invention is, therefore, to provide an improved elastomeric ejection system for submarines, the system featuring a substantially silent check valve, the operation of which is not readily detectable by other vessels.
With the above and other objects in view, a feature of the invention is the provision of an elastomeric ejection system for launching bodies from a submarine. The system comprises a pump for transferring seawater from outside the submarine to an elastomeric disk or structure and a check valve adapted to open to permit the pump to transfer the seawater to the elastomeric disk or structure, and adapted to rapidly close upon filling of the elastomeric disk or structure and expanding of the elastomeric disk or structure. The check valve is provided with a head and a seat portion, a stem portion having fixed thereon the head and a disk having a circular protrusion extending toward the valve seat portion, an annular cup stationarily mounted around the stem portion and having a circular depression in a surface thereof, the depression configured complementarily to the disk protrusion, and holes disposed in the cup and radially extending from the depression to an outer wall of the cup. In closure of the check valve, the disk circular protrusion enters the cup depression, forcing seawater in the depression to exit the cup through the flow restrictive paths comprised by the primary path of the decreasing annular gap between the disk protrusion and cup depression and the secondary path of the radial holes, to slow the valve stem portion, and thereby the valve head in movement into engagement with the valve seat portion.
The above and other features of the invention, including various novel details of construction and combinations of parts, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular system embodying the invention is shown by way of illustration only and not as a limitation of the invention. The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention.